21122010121 has 4 divisors (see below), whose sum is σ = 21468272644. Its totient is φ = 20775747600.

The previous prime is 21122010109. The next prime is 21122010127. The reversal of 21122010121 is 12101022112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11650827721 + 9471182400 = 107939^2 + 97320^2 .

It is a cyclic number.

It is not a de Polignac number, because 21122010121 - 2⁹ = 21122009609 is a prime.

It is a super-2 number, since 2×21122010121² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21122010127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 173131170 + ... + 173131291.

It is an arithmetic number, because the mean of its divisors is an integer number (5367068161).

Almost surely, 2^21122010121 is an apocalyptic number.

It is an amenable number.

21122010121 is a deficient number, since it is larger than the sum of its proper divisors (346262523).

21122010121 is an equidigital number, since it uses as much as digits as its factorization.

21122010121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346262522.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21122010121 its reverse (12101022112), we get a palindrome (33223032233).

The spelling of 21122010121 in words is "twenty-one billion, one hundred twenty-two million, ten thousand, one hundred twenty-one".